230 ABDOMEN 



indicated by a whitish line, which marks the union of the 

 fascia transversalis and fascia iliaca. If the transversalis 

 fascia is divided along that line the deep circumflex iliac artery 

 will be exposed. At the anterior superior spine of the ilium 

 the vessel pierces the fascia transversalis, and lies between that 

 and the transversus muscle ; and lastly, about the middle 

 point of the iliac crest, it pierces the transversus muscle, and 

 its terminal twigs ramify between the transversus abdominis 

 and the internal oblique muscles. Thus the artery gradually 

 approaches the surface, as it passes from its origin to its 

 termination. 



The dissector has already seen the ascending branch which 

 it sends upwards between the internal oblique and transverse 

 muscles. 



Art. Epigastrica Superior et Art. Musculo-phrenica. 

 The superior epigastric and the musculo-phrenic arteries are 

 the two terminal branches of the internal mammary artery. 



The superior epigastric 'will be found behind the rectus muscle 

 and within the upper part of its sheath. It gives twigs to 

 the rectus, and anastomoses with the inferior epigastric and 

 the intercostal arteries. 



Dissection. To expose the musculo-phrenic artery detach 

 / the transversus abdominis from its attachments to the rib carti- 

 lages. The artery will be found, if the injection of the arteries 

 has been good, at the level of the eighth or ninth costal cartilage, 

 where it passes through the diaphragm. Follow it along the costal 

 margin, across the abdominal surface of the costal origins of the 

 diaphragm. 



The Musculo-phrenic. In the abdomen the musculo- 

 phrenic artery passes downwards and laterally, along the costal 

 origin of the diaphragm, from the point where it pierces the 

 diaphragm to the last intercostal space. Before or after it 

 enters the abdomen it supplies anterior intercostal branches 

 to the seventh, eighth, and ninth intercostal spaces (see p. 121). 

 After it enters the abdomen it gives branches to the diaphragm, 

 and other branches which anastomose with twigs from the 

 superior epigastric and the lower two aortic intercostal arteries. 



Dissection. The transversus has already been detached from 

 the inguinal ligament and the crest of the ilium (p. 225), and 

 also from the rib cartilages. Now divide it vertically between 

 the ribs and the iliac crest, and throw it towards the median 

 plane, carefully detaching the transversalis fascia from its deep 

 surface. The muscle fibres end anteriorly in an aponeurosis ; 

 the lower part of the aponeurosis, which blends with the lower 



